Whale Safe Impact
Voluntary Vessel Speed Reduction (VSR) Zone & Whale Safe background
VSR data notes
San Francisco data does not include the Monterey Bay National Marine Sanctuary, which was added to the VSR program in 2023. The Whale Safe system that was launched in San Francisco was designed to give whale presence in the San Francisco portion of the VSR zones so we are reporting on them separately here for now. The Monterey Bay stats come from a different data pipeline and the offseason stats are not tracked as regularly.
Whale Safe System Launch Dates
Southern California: September 17, 2020
San Francisco: September 21, 2022
Vessel Speed Reduction Zones
Vessel Speed Reduction Season Dates:
Southern California:
June 4 - December 31, 2018:
May 15 - December 15, 2019
May 15 - December 15, 2020
May 15 - December 15, 2021
May 1 - December 15, 2022
May 1 - December 15, 2023
May 1 , 2024 - January 15, 2025
San Francisco
May 1 - November 15, 2019
May 1 - November 15, 2020
May 1 - November 15, 2021
May 1 - December 15, 2022
May 1 - December 15, 2023
May 1 , 2024 - January 15, 2025
WPR data notes
Blue whale model data might have been retroactively filled in after periods where the server was down. We don’t have this tracked in our data so there may be days where the Whale Presence Rating didn’t take the blue whale model value into account.
Each species has a threshold for each data stream see Methodology for what is considered low-high (0-1). The Whale Presence Rating considers the highest rating of any of the data streams over 5 days. Two species need to have a high rating in order for the overall Whale Presence Rating to be ‘Very High’.
Vessel compliance/cooperation level
Cooperation time series w.r.t. VSR status
Time series grouped by region where grey shaded bars represent time periods when the VSR zone in each respective region was active. Points represent year-month averages pooled across vessel types for each region.
Cooperation table: Zone x Ship category
Table displaying % cooperation grouped by region and ship category. Values in the active and inactive columns represent cooperation by VSR status, and the final column represents the change in cooperation between periods when the VSR is active vs. inactive.
| Ship category | VSR active cooperation (%) | VSR inactive cooperation (%) | Change (%) |
|---|---|---|---|
| Monterey Bay | |||
| bulk | 56.41516 | NA | NA |
| container | 71.99507 | NA | NA |
| fishing | 79.73571 | NA | NA |
| general cargo | 39.58673 | NA | NA |
| other industry | 60.00006 | NA | NA |
| passenger | 48.09752 | NA | NA |
| pleasure | 24.63185 | NA | NA |
| research | 76.55128 | NA | NA |
| ro-ro | 65.13670 | NA | NA |
| tanker | 62.00351 | NA | NA |
| towing/pushing | 79.52811 | NA | NA |
| San Francisco | |||
| bulk | 58.13379 | 37.811502 | -20.3222859 |
| container | 67.63435 | 30.487235 | -37.1471159 |
| fishing | 25.61000 | 84.623333 | 59.0133333 |
| general cargo | 44.29325 | 36.075447 | -8.2178062 |
| other industry | 51.94873 | 56.620221 | 4.6714908 |
| passenger | 48.72211 | 18.802619 | -29.9194954 |
| pleasure | 10.21415 | 6.872143 | -3.3420035 |
| research | 64.79967 | 52.764328 | -12.0353416 |
| ro-ro | 69.32563 | 37.090640 | -32.2349914 |
| tanker | 65.69202 | 35.694435 | -29.9975856 |
| towing/pushing | 79.18797 | 74.009009 | -5.1789630 |
| Southern California | |||
| bulk | 70.07931 | 60.473503 | -9.6058060 |
| container | 75.66559 | 57.991820 | -17.6737659 |
| fishing | 72.28187 | 65.010526 | -7.2713487 |
| general cargo | 59.09313 | 58.628251 | -0.4648776 |
| other industry | 71.31535 | 74.017635 | 2.7022831 |
| passenger | 45.43029 | 48.072736 | 2.6424482 |
| pleasure | 39.04593 | 25.476143 | -13.5697918 |
| research | 54.37780 | 54.831314 | 0.4535181 |
| ro-ro | 75.00277 | 47.438869 | -27.5638977 |
| tanker | 79.93422 | 68.444962 | -11.4892586 |
| towing/pushing | 91.19411 | 90.767121 | -0.4269873 |
Changes in cooperation by ship category
Monterey Bay is not included in this analysis given that no data on cooperation rates during inactive VSR seasons are available.
Changes in cooperation time series
Monterey Bay is not included in this analysis given that no data on cooperation rates during inactive VSR seasons are available.
Whale presence rating and vessel compliance
Whale presence rating and VSR zone activity
Percent of data where the VSR zone was active vs. inactive, and within VSR status groupings, what the whale presence rating was. Monterey Bay is not included in this analysis as there is no whale presence rating data available.
Whale presence rating and VSR status timeseries
Whale presence rating and vessel cooperation
Percent cooperation grouped by VSR status (inactive vs. active) and whale presence rating. Here, we are only plotting cooperation data between 15-85% to remove those who never cooperate, and those who might always “cooperate” due to external factors (i.e., vessel speed capacity).
San Francisco
Southern California
Whale sightings data and vessel cooperation time series
Blue whale data streams time series
Across metrics, data points represent the year-month average for blue whales. Light grey shaded regions represent seasons when the VSR is active, while the striped regions represent when data was unavailable from the respective source.
For the acoustics panels, year-month averages were done by assigning a “Low Rating” a 1, a “Medium Rating” a 2, a “High Rating” a 3, and “offline” an NA. Then, averages were taken of these scores, and the means were plotted as they fit across the ranges of these three bins.
| Region (n = days) | System | Percent days offline |
|---|---|---|
| San Francisco (n = 846) | Acoustics | 56.03% |
| Southern California (n = 1579) | Acoustics | 24.64% |
| San Francisco (n = 846) | Whale Watch | 20.09% |
| Southern California (n = 1579) | Whale Watch | 11.40% |
Blue whale data stream time series x year
As an example, we could also plot the data as a ridge line plot. This is presenting data across years for just the Southern California VSR zone. This plot style is repeated below and only shows data for the SoCal zone.
Correlation analysis for both zones: Confirmed whale occurrence and WhaleWatch predictions
Pearson’s
sf_corr <- wpr_join %>% filter(zone == "SF VSR")
socal_corr <- wpr_join %>% filter(zone == "Socal VSR")
#SF
cor.test(sf_corr$bwmv, sf_corr$bw_ac_score)
Pearson's product-moment correlation
data: sf_corr$bwmv and sf_corr$bw_ac_score
t = 45.826, df = 4283, p-value < 2.2e-16
alternative hypothesis: true correlation is not equal to 0
95 percent confidence interval:
0.5531430 0.5933383
sample estimates:
cor
0.5735858 #Socal
cor.test(socal_corr$bwmv, socal_corr$bw_ac_score)
Pearson's product-moment correlation
data: socal_corr$bwmv and socal_corr$bw_ac_score
t = 35.259, df = 80478, p-value < 2.2e-16
alternative hypothesis: true correlation is not equal to 0
95 percent confidence interval:
0.1165298 0.1301373
sample estimates:
cor
0.1233394 Spearman’s
#SF
cor.test(sf_corr$bwmv, sf_corr$bw_ac_score, method = "spearman")
Spearman's rank correlation rho
data: sf_corr$bwmv and sf_corr$bw_ac_score
S = 4472725166, p-value < 2.2e-16
alternative hypothesis: true rho is not equal to 0
sample estimates:
rho
0.6589084 #Socal
cor.test(socal_corr$bwmv, socal_corr$bw_ac_score, method = "spearman")
Spearman's rank correlation rho
data: socal_corr$bwmv and socal_corr$bw_ac_score
S = 7.2923e+13, p-value < 2.2e-16
alternative hypothesis: true rho is not equal to 0
sample estimates:
rho
0.1606363 Kendall’s
#SF
cor.test(sf_corr$bwmv, sf_corr$bw_ac_score, method = "kendall")
Kendall's rank correlation tau
data: sf_corr$bwmv and sf_corr$bw_ac_score
z = 43.853, p-value < 2.2e-16
alternative hypothesis: true tau is not equal to 0
sample estimates:
tau
0.5408426 #Socal
cor.test(socal_corr$bwmv, socal_corr$bw_ac_score, method = "kendall")
Kendall's rank correlation tau
data: socal_corr$bwmv and socal_corr$bw_ac_score
z = 45.557, p-value < 2.2e-16
alternative hypothesis: true tau is not equal to 0
sample estimates:
tau
0.1297058 Pearson’s
#SF
cor.test(sf_corr$bwmv, sf_corr$s_bluecount)
Pearson's product-moment correlation
data: sf_corr$bwmv and sf_corr$s_bluecount
t = 25.259, df = 11824, p-value < 2.2e-16
alternative hypothesis: true correlation is not equal to 0
95 percent confidence interval:
0.2090974 0.2432993
sample estimates:
cor
0.2262681 #Socal
cor.test(socal_corr$bwmv, socal_corr$s_bluecount)
Pearson's product-moment correlation
data: socal_corr$bwmv and socal_corr$s_bluecount
t = 36.803, df = 104622, p-value < 2.2e-16
alternative hypothesis: true correlation is not equal to 0
95 percent confidence interval:
0.1070655 0.1190295
sample estimates:
cor
0.1130516 Spearman’s
#SF
cor.test(sf_corr$bwmv, sf_corr$s_bluecount, method = "spearman")
Spearman's rank correlation rho
data: sf_corr$bwmv and sf_corr$s_bluecount
S = 2.0655e+11, p-value < 2.2e-16
alternative hypothesis: true rho is not equal to 0
sample estimates:
rho
0.2507044 #Socal
cor.test(socal_corr$bwmv, socal_corr$s_bluecount, method = "spearman")
Spearman's rank correlation rho
data: socal_corr$bwmv and socal_corr$s_bluecount
S = 1.635e+14, p-value < 2.2e-16
alternative hypothesis: true rho is not equal to 0
sample estimates:
rho
0.1434296 Kendall’s
#SF
cor.test(sf_corr$bwmv, sf_corr$s_bluecount, method = "kendall")
Kendall's rank correlation tau
data: sf_corr$bwmv and sf_corr$s_bluecount
z = 27.384, p-value < 2.2e-16
alternative hypothesis: true tau is not equal to 0
sample estimates:
tau
0.2070631 #Socal
cor.test(socal_corr$bwmv, socal_corr$s_bluecount, method = "kendall")
Kendall's rank correlation tau
data: socal_corr$bwmv and socal_corr$s_bluecount
z = 46.445, p-value < 2.2e-16
alternative hypothesis: true tau is not equal to 0
sample estimates:
tau
0.1170324 | Correlation | Method | Correlation metric |
|---|---|---|
| San Francisco | ||
| bw_ac_score~bwmv | pearson | 0.5735858 |
| bw_ac_score~bwmv | kendall | 0.5408426 |
| bw_ac_score~bwmv | spearman | 0.6589084 |
| Southern California | ||
| bw_ac_score~bwmv | pearson | 0.1233394 |
| bw_ac_score~bwmv | kendall | 0.1297058 |
| bw_ac_score~bwmv | spearman | 0.1606363 |
| Correlation | Method | Correlation metric |
|---|---|---|
| San Francisco | ||
| s_bluecount~bwmv | pearson | 0.2262681 |
| s_bluecount~bwmv | kendall | 0.2070631 |
| s_bluecount~bwmv | spearman | 0.2507044 |
| Southern California | ||
| s_bluecount~bwmv | pearson | 0.1130516 |
| s_bluecount~bwmv | kendall | 0.1170324 |
| s_bluecount~bwmv | spearman | 0.1434296 |